CN114508399A

CN114508399A - Camshaft, valve control structure and engine

Info

Publication number: CN114508399A
Application number: CN202210108750.5A
Authority: CN
Inventors: 林志成; 廖润强
Original assignee: Jiangmen Dachangjiang Group Co Ltd
Current assignee: Jiangmen Dachangjiang Group Co Ltd
Priority date: 2022-01-28
Filing date: 2022-01-28
Publication date: 2022-05-17

Abstract

The invention discloses a camshaft, a valve control structure and an engine, wherein the camshaft comprises a shaft body, the shaft body is provided with a mounting groove, the mounting groove extends along the axial direction of the shaft body, the mounting groove is provided with a notch facing along the radial direction of the shaft body, and the mounting groove is used for mounting a decompression cam so that the decompression cam can rotate relative to the camshaft; the shaft body is provided with a limiting part, the limiting part is positioned at the edge of the notch, and the limiting part is used for limiting the radial movement of the pressure reducing cam; the valve control structure comprises the camshaft, the chain wheel and the decompression mechanism; the engine includes the aforementioned valve control structure. The mounting groove is used for being matched with a decompression cam, so that the decompression cam can rotate relative to the shaft body to jack up or put down the valve rocker; and through the setting of spacing portion, restrict the radial float of decompression cam, avoid producing the abnormal sound because of radial float to ensure the normal realization of decompression function.

Description

Camshaft, valve control structure and engine

Technical Field

The invention relates to the technical field of engines, in particular to a camshaft, a valve control structure and an engine.

Background

The camshaft is one of the important parts of the engine and is mainly used for controlling the opening and closing of the valve, and the camshaft and the pressure reducing mechanism are matched to form a valve control structure. The decompression mechanism comprises a decompression cam and a decompression rocker arm, the decompression cam is rotatably arranged on the camshaft and can rotate relative to the camshaft, and the decompression rocker arm is used for enabling the decompression cam to rotate relative to the camshaft.

When the engine is not started, the pressure reducing rocker arm is in a closed state under the reset action of the spring and keeps the pressure reducing cam jacking the valve rocker arm, so that the valve keeps an open state; at the initial starting stage of the engine, the decompression rocker arm slightly swings along with the rotation of the camshaft and drives the decompression cam to rotate relative to the camshaft, but the valve is still in a slightly opened state at the moment so as to reduce the starting energy consumption; after the engine is started stably, the decompression rocker arm is completely opened, so that the decompression cam does not jack up the valve rocker arm any more, the valve is in a closed state, and the starting process of the engine is completed. The traditional camshaft is matched with the decompression cam through the groove, so that the decompression cam can rotate relative to the camshaft. However, the groove, while rotating the decompression cam relative to the camshaft, may also cause the decompression cam to have radial play relative to the camshaft, which may cause abnormal noise and even a great reduction in decompression function, which may ultimately affect the normal performance of the engine.

Disclosure of Invention

Based on this, it is necessary to provide a camshaft, a valve control structure, and an engine; the camshaft can inhibit the pressure reducing cam from moving in the radial direction relative to the camshaft, avoids abnormal sound and ensures the normal exertion of the pressure reducing function; the valve control structure adopts the camshaft, so that the radial movement of the decompression cam relative to the camshaft can be avoided, and the normal opening and closing of the valve can be ensured; the engine adopts the valve control structure, so that the normal opening and closing of the valve can be ensured, and the performance of the engine is ensured.

The technical scheme is as follows:

one embodiment provides a camshaft, which comprises a shaft body, wherein the shaft body is provided with a mounting groove, the mounting groove is formed along the axial extension of the shaft body, the mounting groove is provided with a notch facing along the radial direction of the shaft body, and the mounting groove is used for mounting a decompression cam so that the decompression cam can rotate relative to the camshaft; the shaft body is provided with a limiting part, the limiting part is located at the edge of the notch, and the limiting part is used for limiting the radial movement of the pressure reducing cam.

The mounting groove of the camshaft is matched with the decompression cam, so that the decompression cam can rotate relative to the shaft body to jack up or put down the valve rocker; and through the setting of spacing portion, restrict the radial float of decompression cam, avoid producing the abnormal sound because of radial float to ensure the normal realization of decompression function.

The technical solution is further explained below:

in one embodiment, the mounting slot is a circular slot having an axis that is not collinear with the axis of the shaft body, and the width of the slot opening is less than the diameter of the circular slot.

In one embodiment, the depth of the circular groove is greater than the radius of the circular groove, and the edge portion of the notch forms the stopper.

In one of the embodiments, the length of the notch in the axial direction of the shaft body is smaller than the length of the circular groove in the axial direction of the shaft body, the notch being for enabling the cam portion of the pressure-reducing cam to be brought into abutting engagement with the rocker arm;

or the length of the notch in the axial direction of the shaft body is equal to the length of the circular groove in the axial direction of the shaft body.

In one embodiment, the shaft body is further provided with a groove sealing part for sealing the notch, and the length of the groove sealing part in the axial direction of the shaft body is smaller than that of the mounting groove in the axial direction of the shaft body; the groove sealing part enables a groove hole to be formed in the part where the sealed installation groove is located, and the groove hole enables the decompression cam to pass through and enables the decompression cam to rotate in the groove hole.

In one embodiment, the seal groove portion is a step provided around the outer circumference of the shaft body; the length of the seal groove portion in the axial direction of the shaft body is smaller than the diameter of the relief cam.

In one embodiment, the groove sealing part is positioned in the middle of the mounting groove; or the groove sealing part is positioned between the middle position of the mounting groove and the tail end position of the mounting groove.

Another embodiment provides a valve control structure including:

the camshaft according to any one of the above aspects;

the chain wheel is fixed at the end part of the camshaft and is coaxially arranged with the camshaft;

the pressure reducing mechanism comprises a pressure reducing cam, a pressure reducing rocker arm and a resetting piece, the pressure reducing cam passes through the mounting groove is rotatably arranged on the cam shaft, the pressure reducing rocker arm is arranged at one end of the pressure reducing cam, the pressure reducing rocker arm can drive the pressure reducing cam to rotate relative to the cam shaft, and the resetting piece is used for enabling the pressure reducing rocker arm to reset.

In the valve control structure, at the initial starting stage of the engine, the chain wheel and the camshaft rotate, the decompression rocker arm swings and drives the decompression cam to rotate relative to the camshaft, at the moment, the decompression cam still jacks the valve rocker arm, and the valve is approximately in a slightly opened state; when the engine is started stably, the rotating speed of the camshaft is at a certain constant speed, at the moment, the decompression rocker arm is completely thrown away, so that the decompression cam does not jack up the valve rocker arm any more, the valve is in a closed state, and the engine is started completely. Because the camshaft has spacing portion, has restricted the radial float of decompression cam to avoid the abnormal sound that leads to because of decompression cam radial float, and ensured the normal realization of decompression function.

The technical solution is further explained below:

in one embodiment, the decompression cam has a spindle, the decompression rocker arm is provided at one end of the spindle, and a cam portion is provided at the other end of the spindle, the cam portion being adapted to be in abutting engagement with the valve rocker arm.

Still another embodiment provides an engine including the valve control structure according to the above technical solution.

Above-mentioned engine adopts aforementioned valve control structure, through the setting of spacing portion for the decompression cam can not produce radial float, and avoided the abnormal sound because of radial float leads to, and guaranteed the normal realization of decompression function, thereby ensured the normal performance of engine.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Furthermore, the drawings are not drawn to a 1:1 scale, and the relative sizes of the various elements in the drawings are drawn only by way of example, and not necessarily to true scale.

FIG. 1 is a schematic structural diagram of closing of a pressure reducing rocker arm and opening of a valve in an embodiment of the invention;

FIG. 2 is a front view of the embodiment of FIG. 1 with the pressure reducing rocker arm closed and the valve open;

FIG. 3 is a schematic structural diagram of opening of a pressure reducing rocker arm and closing of a valve in the embodiment of the invention;

FIG. 4 is a front view of the embodiment of FIG. 3 with the pressure reducing rocker arm open and the valve closed;

FIG. 5 is a schematic view of the assembly structure of the decompression rocker arm, the decompression cam, the reset member, the sprocket and the camshaft in the embodiment of the invention;

FIG. 6 is a schematic view showing an assembly structure of a decompression rocker arm, a decompression cam and a camshaft in the embodiment of the invention;

FIG. 7 is an exploded view of the decompression cam and camshaft of the embodiment of FIG. 6;

FIG. 8 is a schematic view showing the overall construction of the camshaft in the embodiment of FIG. 6;

FIG. 9 is an overall structural front view of the camshaft in the embodiment of FIG. 6;

fig. 10 is a sectional view showing the entire construction of the camshaft in the embodiment of fig. 6.

Reference is made to the accompanying drawings in which:

100. a camshaft; 110. a shaft body; 111. mounting grooves; 112. a notch; 113. a limiting part; 114. a groove sealing part; 210. a decompression cam; 211. a main shaft; 212. a cam portion; 220. a pressure reducing rocker arm; 230. a reset member; 240. a gasket; 250. a pressure reduction baffle plate; 260. a set screw; 300. a sprocket; 400. a bearing; 500. a valve rocker.

Detailed Description

Embodiments of the present invention are described in detail below with reference to the accompanying drawings:

in order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Referring to fig. 6 to 10, an embodiment provides a camshaft 100, including a shaft body 110, where the shaft body 110 is provided with a mounting groove 111, the mounting groove 111 extends along an axial direction of the shaft body 110, the mounting groove 111 has a notch 112 facing in a radial direction of the shaft body 110, and the mounting groove 111 is used for mounting a decompression cam 210, so that the decompression cam 210 can rotate relative to the camshaft 100; the shaft body 110 has a limiting portion 113, the limiting portion 113 is located at an edge of the notch 112, and the limiting portion 113 is used for limiting the radial play of the pressure reducing cam 210.

In the camshaft 100, the mounting groove 111 is used for being matched with the decompression cam 210, so that the decompression cam 210 can rotate relative to the shaft body 110 to jack up or lower the valve rocker 500; by the arrangement of the limiting part 113, the radial play of the pressure reducing cam 210 is limited, abnormal sound caused by the radial play is avoided, and normal realization of a pressure reducing function is ensured.

As seen in the perspective view of fig. 10, the longitudinal direction of the camshaft 100 is the left-right direction, and the extending direction of the mounting groove 111 is also the left-right direction. As shown in the perspective view of fig. 7, the mounting groove 111 has a notch 112, and the notch 112 faces upward, i.e., in a radial direction of the camshaft 100. In the embodiment shown in fig. 6, the decompression cam 210 is mounted on the camshaft 100 through the mounting groove 111, and a part of the decompression cam 210 is exposed through the notch 112, as shown in fig. 7 and 8, due to the arrangement of the limiting portion 113, the limiting portion 113 limits the freedom of movement of the decompression cam 210 in the radial direction, so that the decompression cam 210 cannot move in the radial direction, and abnormal noise caused by the radial movement is avoided.

It can be understood that:

the cam portion 212 of the decompression cam 210 is exposed through the notch 112 of the mounting groove 111, and when the decompression cam 210 rotates, the cam portion 212 can jack up or lower the valve rocker 500, enabling the opening and closing of the valve.

In one embodiment, referring to fig. 7 and 8, the mounting groove 111 is a circular groove having an axis that is not collinear with the axis of the shaft body 110, and the width of the notch 112 is smaller than the diameter of the circular groove.

In the embodiment shown in fig. 7 and 8, the mounting groove 111 is a circular groove, which means that: the groove profile of the mounting groove 111 is circular, the decompression cam 210 comprises a main shaft 211 and a cam part 212, the main shaft 211 is a shaft with a circular section, the section of the mounting groove 111 is the same as that of the main shaft 211, namely, the diameter of the main shaft 211 is approximately equal to or equal to that of the mounting groove 111, but the decompression cam 210 can be ensured to rotate relative to the camshaft 100 in the mounting groove 111. With such an arrangement, the installation groove 111 is substantially equivalent to the decompression cam 210, the structure is compact after installation, and the phenomenon that the decompression cam 210 moves due to a large gap between the groove walls of the installation groove 111 is avoided.

In one embodiment, referring to fig. 7 and 8, the depth of the circular groove is greater than the radius of the circular groove, and the edge portion of the notch 112 forms the stopper 113.

In the embodiment shown in fig. 7 and 8, the mounting groove 111 is a circular groove to match the decompression cam 210 having the main shaft 211 with a circular section. The depth of the circular groove is greater than the diameter of the circular groove, and the edge portion of the notch 112 forms a stopper 113, that is: after the decompression cam 210 is installed on the camshaft 100 through the installation groove 111, since the width of the notch 112 is smaller than the diameter of the installation groove 111, the diameter of the installation groove 111 is approximately equal to the diameter of the main shaft 211 of the decompression cam 210, so that the width of the notch 112 is smaller than the diameter of the main shaft 211 of the decompression cam 210, and meanwhile, the depth of the installation groove 111 is larger than the radius of the installation groove 111, so that the installation groove 111 forms an annular surrounding structure larger than a semicircle, and the decompression cam 210 installed therein is limited by the notch 112 and is difficult to move radially, thereby playing a role of limiting the radial movement of the decompression cam 210. At this time, the edge portion of the notch 112 forms a stopper portion 113, and the stopper portion 113 corresponds to a portion of the camshaft 100 and serves to restrict the radial play of the decompression cam 210.

In one embodiment, the length of the notch 112 in the axial direction of the shaft body 110 is smaller than the length of the circular groove in the axial direction of the shaft body 110, and the notch 112 is used to enable the cam portion 212 of the decompression cam 210 to be in abutting engagement with the rocker arm 500.

In this embodiment, the length of the notch 112 is not the same as that of the mounting groove 111, that is, a part of the mounting groove 111 does not have the notch 112 and is a closed slot, and the other part has the notch 112, the notch 112 exposes the cam portion 212 of the decompression cam 210 so that the cam portion 212 can abut against the valve rocker 500, and when the decompression cam 210 rotates, the cam portion 212 lifts up or down the valve rocker 500 to perform a function of opening or closing the valve.

In another embodiment, the length of the notch 112 in the axial direction of the shaft body 110 is equal to the length of the circular groove in the axial direction of the shaft body 110.

Optionally, the length of the mounting groove 111 may be half of the length of the shaft body 110, the slots 112 are formed in the length range of the mounting groove 111, and the mounting groove 111 is of a groove structure in which the width of the slot 112 is smaller than the diameter of the mounting groove 111 and the groove cross section of the mounting groove 111 is larger than a half circle, so that the mounting groove 111 can realize the radial play limiting function of the decompression cam 210.

In one embodiment, referring to fig. 6 to 10, the shaft body 110 is further provided with a sealing groove portion 114, the sealing groove portion 114 is used for sealing the notch 112, and the length of the sealing groove portion 114 in the axial direction of the shaft body 110 is smaller than the length of the mounting groove 111 in the axial direction of the shaft body 110; the groove sealing portion 114 forms a groove hole in a portion where the mounting groove 111 is closed, and the groove hole enables the decompression cam 210 to pass through and the decompression cam 210 to rotate therein.

In the embodiment shown in fig. 8 to 10, the groove-sealing portion 114 does not seal all the notches 112, but only seals some of the notches 112, leaving at least the area of the notches 112 where the cam portion 212 of the decompression cam 210 can come into abutment with the valve rocker arm 500. The slot-closing portion 114 provides a slot in the closed region that enables the decompression cam 210 to pass through, and also enables a corresponding portion of the decompression cam 210 to rotate within the slot relative to the camshaft 100.

Alternatively, the portion of the groove sealing part 114 facing the mounting groove 111 has an arc-shaped surface, and the arc-shaped surface and the groove wall of the mounting groove 111 cooperate to form a circular groove hole, which has the same section as the main shaft 211 of the decompression cam 210.

It can be understood that:

the slot sealing portion 114 may be integrally formed with the camshaft 100, and is a circular slot formed when the mounting slot 111 is formed.

In one embodiment, referring to fig. 6 to 9, the groove sealing portion 114 is a step disposed around the outer circumference of the shaft body 110.

As shown in fig. 6 and 7, the groove sealing portion 114 is a step provided around the outer circumference of the shaft body 110, and the step may be provided integrally with the shaft body 110.

As shown in fig. 1, 3 and 5, the step formed by the groove sealing portion 114 can also be used as a limit structure for mounting the bearing 400 on the camshaft 100, so as to form a limit shoulder, which is not described again.

In the embodiment shown in fig. 6, the mounting groove 111 is roughly divided into three parts by the step formed by the groove sealing portion 114, the open section (with the notch 112) at the left end of the groove sealing portion 114, the closed section (without the notch 112) where the groove sealing portion 114 is located, and the working section (with the notch 112, which is roughly a section corresponding to the cam portion 212 of the decompression cam 210) at the right end of the groove sealing portion 114, and the mounting groove 111 in the view of fig. 6 also passes through the non-solid part of the camshaft 100, so that there is a section without an area surrounding the decompression cam 210, which is not described again.

It can be understood that:

the opening section can reduce the friction between the decompression cam 210 and the camshaft 100, play a role in limiting the radial play of the decompression cam 210, and simultaneously, can be filled with oil to lubricate the decompression cam 210; the closed section plays a role in limiting radial play of the decompression cam 210 and can also play a role in reducing friction between the decompression cam 210 and the camshaft 100; the operation stage enables the cam portion 212 of the decompression cam 210 to abut against the valve rocker 500 (e.g., a roller of the valve rocker 500) and restricts radial play of the decompression cam 210.

In one embodiment, referring to fig. 9 and 10, the length of the groove sealing portion 114 in the axial direction of the shaft body 110 is smaller than the diameter of the relief cam 210.

In the embodiment shown in fig. 9 and 10, the width of the groove sealing portion 114 is small, smaller than the diameter of the decompression cam 210, or smaller than the diameter of the circular mounting groove 111.

In one embodiment, referring to fig. 9 and 10, the slot sealing portion 114 is located at a middle position of the mounting groove 111; or the groove sealing part 114 is positioned between the middle position of the mounting groove 111 and the end position of the mounting groove 111.

In the embodiment shown in fig. 10, the step formed by the groove sealing portion 114 is located substantially at the middle position of the length of the mounting groove 111, or between the middle position and the end position of the mounting groove 111 (i.e., the position of the mounting groove 111 corresponding to the cam portion 212 of the decompression cam 210), which may also be understood as the second half position of the mounting groove 111.

Referring to fig. 1 to 5, another embodiment provides a valve control structure, including:

the camshaft 100 according to any of the above embodiments;

a sprocket 300, wherein the sprocket 300 is fixed on the end of the camshaft 100, and the sprocket 300 is arranged coaxially with the camshaft 100;

decompression mechanism, decompression mechanism includes decompression cam 210, decompression rocking arm 220 and resets 230, decompression cam 210 passes through mounting groove 111 rotates and establishes on camshaft 100, decompression rocking arm 220 establishes decompression cam 210's one end, decompression rocking arm 220 can drive decompression cam 210 is relative camshaft 100 rotates, it is used for making to reset 230 decompression rocking arm 220 resets.

In the valve control structure, at the initial starting stage of the engine, the chain wheel 300 and the camshaft 100 rotate, the decompression rocker arm 220 swings and drives the decompression cam 210 to rotate relative to the camshaft 100, at the moment, the decompression cam 210 still jacks the valve rocker arm 500, and the valve is approximately in a slightly opened state; after the engine is started stably, the rotation speed of the camshaft 100 is at a certain constant speed, at this time, the decompression rocker arm 220 is completely thrown away, so that the decompression cam 210 no longer jacks up the valve rocker arm 500, the valve is in a closed state, and the engine is started completely. Because the camshaft 100 has the limiting portion 113, the radial play of the decompression cam 210 is limited, thereby avoiding abnormal noise caused by the radial play of the decompression cam 210 and ensuring the normal realization of the decompression function.

In one embodiment, referring to fig. 7, the decompression cam 210 has a main shaft 211 and a cam portion 212, the decompression rocker arm 220 is disposed at one end of the main shaft 211, the cam portion 212 is disposed at the other end of the main shaft 211, and the cam portion 212 is configured to be in abutting engagement with the valve rocker arm 500.

Alternatively, the other end of the main shaft 211 has a horizontal cut surface that causes the other end of the main shaft 211 to form the cam portion 212. When the main shaft 211 rotates, if the horizontal section is in a horizontal state, the height of the horizontal section is low, and the valve rocker 500 is difficult to jack, and when the horizontal section is in a non-horizontal state, the height of the horizontal section is relatively high, so that the valve rocker 500 can be jacked, and further description is omitted.

In one embodiment, referring to fig. 1 and 3, the pressure reducing mechanism further includes a spacer 240, the spacer 240 is fixed on the sprocket 300, and the spacer 240 is located between the sprocket 300 and the pressure reducing rocker arm 220.

Alternatively, as shown in fig. 1 and 3, the reset member 230 is a torsion spring, one end of the torsion spring is fixed to the washer 240, and the other end of the torsion spring is fixed to the pressure reducing rocker arm 220, and when not in operation, the torsion spring keeps the pressure reducing rocker arm 220 in a closed state, so that the pressure reducing cam 210 jacks up the valve rocker arm 500, and the valve is in an open state. When operating, the decompression rocker arm 220 overcomes the force of the torsion spring and gradually opens fully, causing the decompression cam 210 to lower the valve rocker arm 500, thereby closing the valve.

In one embodiment, referring to fig. 1 to 4, the decompression mechanism further includes a decompression flap 250 and a fixing screw 260, the fixing screw 260 fixes the decompression flap 250 to the sprocket 300, and the decompression flap 250 and the decompression rocker arm 220 are both located on the same side of the sprocket 300.

The relief flap 250 has a stop surface to limit axial play of the relief rocker arm 220, which may also be understood as limiting axial play of the relief cam 210 and will not be described in detail.

Yet another embodiment provides an engine including the valve control structure as described in the above embodiment.

The engine adopts the valve control structure, and the limiting part 113 is arranged, so that the decompression cam 210 cannot generate radial play, abnormal sound caused by the radial play is avoided, normal realization of a decompression function is ensured, and normal performance of the engine is ensured.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A camshaft is characterized by comprising a shaft body, wherein the shaft body is provided with a mounting groove, the mounting groove is formed in the axial extension of the shaft body, the mounting groove is provided with a notch facing in the radial direction of the shaft body, and the mounting groove is used for mounting a decompression cam so that the decompression cam can rotate relative to the camshaft; the shaft body is provided with a limiting part, the limiting part is located at the edge of the notch, and the limiting part is used for limiting the radial movement of the pressure reducing cam.

2. The camshaft of claim 1 wherein the mounting slot is a circular slot having an axis that is non-collinear with the axis of the shaft body, the width of the slot opening being less than the diameter of the circular slot.

3. The camshaft defined in claim 2, wherein the depth of the circular groove is greater than the radius of the circular groove, and the edge portion of the notch forms the stopper.

4. The camshaft according to claim 3, wherein a length of the notch in the axial direction of the shaft body is smaller than a length of the circular groove in the axial direction of the shaft body, the notch being for enabling the cam portion of the decompression cam to be brought into abutting engagement with a rocker arm;

5. The camshaft according to any one of claims 1 to 4, wherein the shaft body is further provided with a groove seal portion for closing the notch, the length of the groove seal portion in the axial direction of the shaft body being smaller than the length of the mounting groove in the axial direction of the shaft body; the groove sealing part enables a groove hole to be formed in the part where the sealed installation groove is located, and the groove hole enables the decompression cam to pass through and enables the decompression cam to rotate in the groove hole.

6. The camshaft of claim 5, wherein the groove seal portion is a step provided around an outer periphery of the shaft body; the length of the seal groove portion in the axial direction of the shaft body is smaller than the diameter of the relief cam.

7. The camshaft of claim 6, wherein the groove sealing portion is located at a middle position of the mounting groove; or the groove sealing part is positioned between the middle position of the mounting groove and the tail end position of the mounting groove.

8. A valve control structure characterized by comprising:

the camshaft of any one of claims 1 to 7;

9. A valve control structure as claimed in claim 8, characterized by said decompression cam having a spindle at one end thereof and a cam portion at the other end thereof for abutting engagement with a valve rocker arm.

10. An engine characterized by comprising the valve control structure according to any one of claims 8 to 9.